JP5045640B2 - Fuel injection control device for in-cylinder internal combustion engine - Google Patents

Fuel injection control device for in-cylinder internal combustion engine Download PDF

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JP5045640B2
JP5045640B2 JP2008276092A JP2008276092A JP5045640B2 JP 5045640 B2 JP5045640 B2 JP 5045640B2 JP 2008276092 A JP2008276092 A JP 2008276092A JP 2008276092 A JP2008276092 A JP 2008276092A JP 5045640 B2 JP5045640 B2 JP 5045640B2
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真吾 中田
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Denso Corp
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Description

本発明は、高圧ポンプにより燃料を高圧にして燃料噴射弁に供給し、この燃料噴射弁から燃料を気筒内に直接噴射する筒内噴射式の内燃機関の制御装置に関する発明である。   The present invention relates to a control apparatus for an in-cylinder injection internal combustion engine in which fuel is made high pressure by a high-pressure pump and supplied to a fuel injection valve, and fuel is directly injected into the cylinder from the fuel injection valve.

気筒内に燃料を直接噴射する筒内噴射エンジンは、吸気ポートに燃料を噴射する吸気ポート噴射エンジンと比較して、噴射から燃焼までの時間が短く、噴射燃料を霧化させる時間を十分に稼ぐことができないため、燃料タンクから低圧ポンプで汲み上げた燃料を、エンジンのカム軸で駆動する高圧ポンプにより昇圧して燃料噴射弁から高圧で燃料を噴射させることで噴射燃料の霧化を促進するようにしている。   An in-cylinder injection engine that directly injects fuel into a cylinder has a shorter time from injection to combustion than an intake port injection engine that injects fuel into an intake port, and has enough time to atomize the injected fuel. Therefore, the fuel pumped up from the fuel tank by the low pressure pump is boosted by the high pressure pump driven by the camshaft of the engine, and the fuel is injected from the fuel injection valve at a high pressure to promote atomization of the injected fuel. I have to.

しかし、燃料噴射弁から高圧で燃料を噴射すると、単位時間当たりの燃料噴射量が多くなり、噴射による燃圧低下が発生する。燃料噴射量の制御は、高圧燃料系の燃圧が目標燃圧に制御されていることを前提として、燃料噴射弁を駆動する噴射パルス幅によって燃料噴射量が制御されるため、燃圧が変動すると、燃料噴射量が変動して空燃比制御精度が悪化してしまう。   However, when fuel is injected at a high pressure from the fuel injection valve, the amount of fuel injection per unit time increases, and a fuel pressure drop due to injection occurs. The fuel injection amount is controlled on the assumption that the fuel pressure of the high-pressure fuel system is controlled to the target fuel pressure, so that the fuel injection amount is controlled by the injection pulse width that drives the fuel injection valve. The injection amount fluctuates and the air-fuel ratio control accuracy deteriorates.

そこで、従来より、燃圧変動による燃料噴射量の変動を抑えるために、燃圧センサで検出した燃圧に応じて噴射パルス幅を補正し、更に、燃圧の高周波変動に影響されて噴射パルス幅が過誤補正されることを防止するために、燃圧センサの検出燃圧をなまし処理等により平滑化処理して、平滑化処理後の検出燃圧に応じて噴射パルス幅を補正するようにしたものがある。   Therefore, conventionally, in order to suppress fluctuations in the fuel injection amount due to fluctuations in the fuel pressure, the injection pulse width is corrected according to the fuel pressure detected by the fuel pressure sensor, and the injection pulse width is erroneously corrected by being affected by high-frequency fluctuations in the fuel pressure. In order to prevent this, the fuel pressure detected by the fuel pressure sensor is smoothed by a smoothing process or the like, and the injection pulse width is corrected according to the detected fuel pressure after the smoothing process.

しかし、従来は、エンジンの過渡運転時と定常運転時とで検出燃圧の平滑化度合が一定であったため、定常運転時の燃圧の高周波変動の影響排除を優先して検出燃圧の平滑化度合を設定すると、過渡運転時の燃圧追従性が低下し、反対に、過渡運転時の燃圧追従性を優先して検出燃圧の平滑化度合を設定すると、定常運転時の燃圧の高周波変動の影響を十分に排除できないという問題があった。   However, in the past, the smoothness of the detected fuel pressure was constant during transient operation and steady operation of the engine, so the priority of eliminating the influence of high-frequency fluctuations in the fuel pressure during steady operation was prioritized. If set, the fuel pressure followability during transient operation is reduced, and conversely, if the smoothing degree of the detected fuel pressure is set with priority given to the fuel pressure followability during transient operation, the influence of high frequency fluctuations in the fuel pressure during steady operation is sufficient. There was a problem that could not be excluded.

そこで、特許文献１（特開平９−２５６８９７号公報）では、エンジンの過渡運転時の燃圧追従性と定常運転時の燃圧の高周波変動の影響排除とを両立させることを目的として、エンジン運転状態が過渡運転状態であるか定常運転状態であるかによって、検出燃圧の平滑化度合を変更することが提案されている。
特開平９−２５６８９７号公報（第２頁等参照） Therefore, in Patent Document 1 (Japanese Patent Application Laid-Open No. 9-256897), the engine operating state is set to satisfy both the fuel pressure followability during transient operation of the engine and the elimination of the influence of high frequency fluctuations in fuel pressure during steady operation. It has been proposed to change the smoothing degree of the detected fuel pressure depending on whether it is a transient operation state or a steady operation state.
Japanese Patent Laid-Open No. 9-256897 (see page 2)

上記特許文献１では、エンジン運転状態が過渡運転状態であるか定常運転状態であるかによって、検出燃圧の平滑化度合を変更するようにしているが、エンジンの過渡運転時に常に目標燃圧が変化するとは限らないため、目標燃圧が変化しないときでも検出燃圧の平滑化度合が燃圧追従性を高める方向に変更されてしまう場合があり、その結果、燃圧の高周波変動の影響を受けやすくなって、噴射パルス幅が過誤補正されて空燃比制御精度が悪化する場合があった。   In Patent Document 1, the smoothing degree of the detected fuel pressure is changed depending on whether the engine operation state is a transient operation state or a steady operation state. However, when the target fuel pressure always changes during engine transient operation. Therefore, even when the target fuel pressure does not change, the smoothing degree of the detected fuel pressure may be changed in a direction that improves the fuel pressure followability, and as a result, the fuel pressure tends to be affected by high-frequency fluctuations in the fuel pressure. In some cases, the pulse width is erroneously corrected and the air-fuel ratio control accuracy deteriorates.

本発明はこのような事情を考慮してなされたものであり、従ってその目的は、燃圧検出手段の検出燃圧の平滑化処理を適正化して空燃比制御精度を向上させることができる筒内噴射式の内燃機関の制御装置を提供することにある。   The present invention has been made in view of such circumstances. Therefore, the object of the present invention is to improve the air-fuel ratio control accuracy by optimizing the smoothing process of the detected fuel pressure of the fuel pressure detecting means. An internal combustion engine control apparatus is provided.

上記目的を達成するために、請求項１に係る発明は、燃料を高圧にして燃料噴射弁に供給する高圧ポンプと、内燃機関の運転条件に応じて前記燃料噴射弁を駆動する噴射パルス幅（噴射時間）を算出する噴射パルス幅算出手段とを備え、前記噴射パルス幅で前記燃料噴射弁を駆動して燃料を気筒内に直接噴射する筒内噴射式内燃機関の燃料噴射制御装置において、前記高圧ポンプにより前記燃料噴射弁に供給される燃料の圧力（以下「燃圧」という）を検出する燃圧検出手段と、前記燃圧検出手段の検出燃圧を平滑化処理する検出燃圧平滑化処理手段と、前記検出燃圧平滑化処理手段で平滑化処理された検出燃圧に基づいて前記噴射パルス幅を補正する噴射パルス幅補正手段とを備え、前記検出燃圧平滑化処理手段は、前記燃圧検出手段の検出燃圧の変動度合に基づいて燃圧の過渡／定常状態を判定する燃圧過渡／定常判定手段と、前記燃圧の過渡／定常状態の判定結果に応じて前記検出燃圧の平滑化度合を変更する手段とを備えていることを特徴とする。ここで、平滑化処理は、例えば、なまし処理、一次遅れ処理、フィルタ処理、加重平均演算等のいずれかを用いれば良い。 In order to achieve the above object, the invention according to claim 1 is a high-pressure pump that supplies fuel to a fuel injection valve at a high pressure, and an injection pulse width that drives the fuel injection valve in accordance with operating conditions of the internal combustion engine ( A fuel injection control device for an in-cylinder internal combustion engine that directly injects fuel into a cylinder by driving the fuel injection valve with the injection pulse width. Fuel pressure detecting means for detecting the pressure of fuel supplied to the fuel injection valve by a high-pressure pump (hereinafter referred to as “fuel pressure”), detected fuel pressure smoothing processing means for smoothing the detected fuel pressure of the fuel pressure detecting means, and a injection pulse width correction means for correcting the injection pulse width based on the detected fuel pressure smoothing detected fuel pressure is smoothed by the processing means, the detected fuel pressure smoothing processing means, detection of the fuel pressure detecting means A fuel pressure transient / steady state determining means for determining a transient / steady state of the fuel pressure based on a degree of fluctuation of the fuel pressure, and a means for changing the smoothing degree of the detected fuel pressure according to the determination result of the transient / steady state of the fuel pressure. It is characterized by having. Here, for the smoothing process, for example, any one of an annealing process, a first-order lag process, a filter process, a weighted average calculation, and the like may be used.

このように、燃圧検出手段の検出燃圧の変動度合に基づいて燃圧の過渡／定常状態を判定し、その燃圧の過渡／定常状態の判定結果に応じて当該検出燃圧の平滑化度合を変更すれば、内燃機関の過渡運転時でも目標燃圧が変化しない場合は、実燃圧（燃圧検出手段の検出燃圧）の変動も少ない燃圧定常状態と判断して、検出燃圧の平滑化度合を燃圧追従性を高める方向に変更することを回避して燃圧の高周波変動の影響を排除することが可能となり、また、内燃機関の定常運転時でも目標燃圧が変化すれば、燃圧過渡状態と判断して検出燃圧の平滑化度合を燃圧追従性を高める方向に変更して実燃圧を応答良く目標燃圧に追従させることが可能となる。これにより、実燃圧の変動度合に応じて燃圧検出手段の検出燃圧の平滑化処理を適正化して空燃比制御精度を向上させることができる。 In this way, if the transient / steady state of the fuel pressure is determined based on the degree of fluctuation of the detected fuel pressure of the fuel pressure detecting means, and the smoothing degree of the detected fuel pressure is changed according to the determination result of the transient / steady state of the fuel pressure. If the target fuel pressure does not change even during transient operation of the internal combustion engine, it is determined that the actual fuel pressure (the detected fuel pressure of the fuel pressure detecting means) does not fluctuate so that the fuel pressure is steady, and the smoothness of the detected fuel pressure is increased. It is possible to avoid the effect of high-frequency fluctuations in the fuel pressure by avoiding the change in direction, and if the target fuel pressure changes even during steady operation of the internal combustion engine, it is judged that the fuel pressure is in a transient state and the detected fuel pressure is smoothed. It is possible to change the chemical degree in a direction to improve the fuel pressure followability and make the actual fuel pressure follow the target fuel pressure with good response. Thereby, the smoothing process of the detected fuel pressure of the fuel pressure detecting means can be optimized according to the fluctuation degree of the actual fuel pressure, and the air-fuel ratio control accuracy can be improved.

しかも、請求項１に係る発明では、燃圧検出手段の検出燃圧の変動度合に基づいて燃圧の過渡／定常状態を燃圧過渡／定常判定手段により判定し、その判定結果に応じて検出燃圧の平滑化度合を変更するようにしているため、実燃圧の過渡／定常状態に応じて検出燃圧の平滑化度合を適正に変更することができる。
この場合、請求項２のように、燃圧過渡状態と判定した時の検出燃圧の平滑化度合を燃圧定常状態と判定した時の検出燃圧の平滑化度合よりも小さい値に設定するようにすると良い。このようにすれば、燃圧定常時の燃圧の高周波変動の影響排除を優先し、且つ、燃圧過渡時の燃圧追従性を優先させた燃圧制御が可能となる。 Moreover, in the invention according to claim 1 , the fuel pressure transient / steady state is determined by the fuel pressure transient / steady state determination means based on the degree of fluctuation of the detected fuel pressure of the fuel pressure detection means, and the detected fuel pressure is smoothed according to the determination result. because you have to change the degree, it is possible to properly change the smoothing degree of detection fuel pressure in accordance with a transient / steady state of the actual fuel pressure.
In this case, as in claim 2, the smoothing degree of the detected fuel pressure when it is determined that the fuel pressure is in a transient state may be set to a value smaller than the smoothing degree of the detected fuel pressure when it is determined that the fuel pressure is in a steady state. . In this way, it is possible to perform fuel pressure control in which priority is given to eliminating the influence of high-frequency fluctuations in the fuel pressure when the fuel pressure is steady, and priority is given to the fuel pressure follow-up performance when the fuel pressure is transient.

この場合、請求項３のように、単位時間当たりの検出燃圧の変動量が所定の燃圧過渡判定値以上であることを検出したときに燃圧過渡状態と判定するようにしても良い。これにより、簡単な処理で燃圧の過渡／定常状態の判定を精度良く行うことができる。   In this case, as in the third aspect, the fuel pressure transient state may be determined when it is detected that the fluctuation amount of the detected fuel pressure per unit time is not less than a predetermined fuel pressure transient determination value. As a result, it is possible to accurately determine the transient / steady state of the fuel pressure with a simple process.

具体的には、燃料噴射弁の燃料噴射により燃圧変動が発生することを考慮して、請求項４のように、前記燃圧過渡判定値は、単位時間当たりの燃料噴射弁の燃料噴射による燃圧変動量を考慮して設定しても良い。或は、高圧ポンプの燃料吐出により燃圧変動が発生することを考慮して、請求項５のように、前記燃圧過渡判定値は、単位時間当たりの高圧ポンプの燃料吐出による燃圧変動量を考慮して設定しても良い。勿論、燃料噴射弁の燃料噴射による燃圧変動量と高圧ポンプの燃料吐出による燃圧変動量の両方を考慮して燃圧過渡判定値を設定しても良い。   Specifically, considering that the fuel pressure fluctuation occurs due to the fuel injection of the fuel injection valve, the fuel pressure transient determination value is the fuel pressure fluctuation caused by the fuel injection of the fuel injection valve per unit time as in claim 4. You may set in consideration of quantity. Alternatively, in consideration of the occurrence of fuel pressure fluctuation due to fuel discharge from the high-pressure pump, the fuel pressure transient determination value takes into account the amount of fuel pressure fluctuation due to fuel discharge from the high-pressure pump per unit time. May be set. Of course, the fuel pressure transient determination value may be set in consideration of both the fuel pressure fluctuation amount due to the fuel injection of the fuel injection valve and the fuel pressure fluctuation amount due to the fuel discharge of the high pressure pump.

前述した請求項１に係る発明では、燃圧検出手段の検出燃圧の変動度合に基づいて燃圧の過渡／定常状態を判定し、その燃圧の過渡／定常状態の判定結果に応じて当該検出燃圧の平滑化度合を変更するようにしたが、目標燃圧の変化に追従して実燃圧（燃圧検出手段の検出燃圧）が変化することを考慮して、請求項６のように、目標燃圧の変化度合に基づいて燃圧の過渡／定常状態を判定し、その燃圧の過渡／定常状態の判定結果に応じて検出燃圧の平滑化度合を変更するようにしても良い。このようにしても、前述した請求項１に係る発明とほぼ同様の効果を得ることができる。 In the invention according to claim 1, the fuel pressure transient / steady state is determined based on the degree of fluctuation of the detected fuel pressure of the fuel pressure detecting means, and the detected fuel pressure is smoothed according to the determination result of the fuel pressure transient / steady state. Although the degree of conversion is changed, the change in the target fuel pressure is changed as in claim 6 in consideration of the change in the actual fuel pressure (the detected fuel pressure of the fuel pressure detecting means) following the change in the target fuel pressure. Based on the determination result of the transient / steady state of the fuel pressure based on the determination result, the smoothing degree of the detected fuel pressure may be changed according to the determination result of the transient / steady state of the fuel pressure. Even if it does in this way, the effect similar to the invention which concerns on Claim 1 mentioned above can be acquired.

この場合も、請求項７のように、燃圧過渡状態と判定した時の検出燃圧の平滑化度合を燃圧定常状態と判定した時の検出燃圧の平滑化度合よりも小さい値に設定するようにすると良い。 Again, as in claim 7, when to set to a value smaller than the smoothing degree of detection fuel pressure when smoothing the detected degree of the fuel pressure when it is determined that the fuel pressure transient is determined that the fuel pressure steady state good.

その他、本発明は、請求項８のように、前記検出燃圧平滑化処理手段は、内燃機関の始動時には検出燃圧の平滑化処理を行わず、始動後に検出燃圧の平滑化処理を開始し、前記噴射パルス幅補正手段は、内燃機関の始動時には平滑化処理されない検出燃圧に基づいて噴射パルス幅を補正し、始動後には平滑化処理された検出燃圧に基づいて噴射パルス幅を補正するようにしても良い。内燃機関の始動時には実燃圧が非常に大きく変動するため、内燃機関の始動時に燃圧検出手段の検出燃圧を平滑化処理すると、検出燃圧と実燃圧とのずれが平滑化処理により拡大されてしまい、内燃機関の始動時の噴射パルス幅補正精度が悪化する可能性があるためである。   In addition, according to the present invention, the detected fuel pressure smoothing processing means does not perform the detected fuel pressure smoothing process when starting the internal combustion engine, and starts the detected fuel pressure smoothing process after starting, The injection pulse width correction means corrects the injection pulse width based on the detected fuel pressure that is not smoothed when the internal combustion engine is started, and corrects the injection pulse width based on the detected fuel pressure that is smoothed after the start. Also good. Since the actual fuel pressure fluctuates very greatly at the start of the internal combustion engine, when the detected fuel pressure of the fuel pressure detection means is smoothed at the start of the internal combustion engine, the deviation between the detected fuel pressure and the actual fuel pressure is enlarged by the smoothing process, This is because the injection pulse width correction accuracy at the start of the internal combustion engine may deteriorate.

以下、本発明を実施するための最良の形態を具体化した２つの実施例１，２を説明する。   Hereinafter, two Examples 1 and 2, which embody the best mode for carrying out the present invention, will be described.

本発明の実施例１を図１乃至図４に基づいて説明する。
まず、図１に基づいて筒内噴射エンジン（内燃機関）の燃料供給システム全体の構成を説明する。 A first embodiment of the present invention will be described with reference to FIGS.
First, based on FIG. 1, the structure of the whole fuel supply system of a cylinder injection engine (internal combustion engine) is demonstrated.

燃料を貯溜する燃料タンク１１内には、燃料を汲み上げる低圧ポンプ１２が設置されている。この低圧ポンプ１２は、バッテリ（図示せず）を電源とする電動モータ（図示せず）によって駆動される。この低圧ポンプ１２から吐出される燃料は、燃料配管１３を通して高圧ポンプ１４に供給される。燃料配管１３には、プレッシャレギュレータ１５が接続され、このプレッシャレギュレータ１５によって低圧ポンプ１２の吐出圧（高圧ポンプ１４への燃料供給圧力）が所定圧力に調圧され、その圧力を越える燃料の余剰分は燃料戻し管１６により燃料タンク１１内に戻されるようになっている。   A low pressure pump 12 that pumps up the fuel is installed in the fuel tank 11 that stores the fuel. The low-pressure pump 12 is driven by an electric motor (not shown) that uses a battery (not shown) as a power source. The fuel discharged from the low pressure pump 12 is supplied to the high pressure pump 14 through the fuel pipe 13. A pressure regulator 15 is connected to the fuel pipe 13, and the discharge pressure of the low-pressure pump 12 (fuel supply pressure to the high-pressure pump 14) is adjusted to a predetermined pressure by the pressure regulator 15, and surplus fuel exceeding that pressure Is returned to the fuel tank 11 by a fuel return pipe 16.

図２に示すように、高圧ポンプ１４は、円筒状のポンプ室１８内でピストン１９を往復運動させて燃料を吸入／吐出するピストンポンプであり、ピストン１９は、エンジンのカム軸２０に嵌着されたカム２１の回転運動によって駆動される。この高圧ポンプ１４の吸入口２３側には、常開型の電磁弁からなる燃圧制御弁２２が設けられている。高圧ポンプ１４の吸入行程（ピストン１９の下降時）においては、燃圧制御弁２２が開弁されてポンプ室１８内に燃料が吸入され、吐出行程（ピストン１９の上昇時）においては、燃圧制御弁２２の閉弁時間（閉弁開始時期からピストン１９の上死点までの閉弁状態の時間）を制御することで、高圧ポンプ１４の吐出量を制御して燃圧（吐出圧力）を制御する。   As shown in FIG. 2, the high-pressure pump 14 is a piston pump that sucks / discharges fuel by reciprocating a piston 19 in a cylindrical pump chamber 18. The piston 19 is fitted to a camshaft 20 of the engine. It is driven by the rotational movement of the cam 21. On the suction port 23 side of the high-pressure pump 14, a fuel pressure control valve 22 comprising a normally open type electromagnetic valve is provided. During the intake stroke of the high-pressure pump 14 (when the piston 19 is lowered), the fuel pressure control valve 22 is opened and fuel is sucked into the pump chamber 18, and during the discharge stroke (when the piston 19 is raised), the fuel pressure control valve. By controlling the valve closing time 22 (the valve closing time from the valve closing start time to the top dead center of the piston 19), the discharge amount of the high-pressure pump 14 is controlled to control the fuel pressure (discharge pressure).

つまり、燃圧を上昇させるときには、燃圧制御弁２２の閉弁開始時期（通電時期）を進角させることで、燃圧制御弁２２の閉弁時間を長くして高圧ポンプ１４の吐出量を増加させ、逆に、燃圧を低下させるときには、燃圧制御弁２２の閉弁開始時期（通電時期）を遅角させることで、燃圧制御弁２２の閉弁時間を短くして高圧ポンプ１４の吐出量を減少させる。   That is, when raising the fuel pressure, the valve closing start timing (energization timing) of the fuel pressure control valve 22 is advanced, thereby extending the valve closing time of the fuel pressure control valve 22 and increasing the discharge amount of the high-pressure pump 14. Conversely, when lowering the fuel pressure, the valve closing start timing (energization timing) of the fuel pressure control valve 22 is retarded, thereby shortening the valve closing time of the fuel pressure control valve 22 and reducing the discharge amount of the high-pressure pump 14. .

一方、高圧ポンプ１４の吐出口２４側には、吐出した燃料の逆流を防止する逆止弁２５が設けられている。図１に示すように、高圧ポンプ１４から吐出された燃料は、高圧燃料配管２６を通してデリバリパイプ２７に送られ、このデリバリパイプ２７からエンジンのシリンダヘッドに気筒毎に取り付けられた燃料噴射弁２８に高圧の燃料が分配される。高圧燃料配管２６には、燃圧を検出する燃圧センサ２９（燃圧検出手段）が設けられ、エンジンのシリンダブロックには、冷却水温を検出する冷却水温センサ３２が設けられている。   On the other hand, a check valve 25 for preventing the backflow of discharged fuel is provided on the discharge port 24 side of the high-pressure pump 14. As shown in FIG. 1, the fuel discharged from the high-pressure pump 14 is sent to a delivery pipe 27 through a high-pressure fuel pipe 26, and from this delivery pipe 27 to a fuel injection valve 28 attached to the cylinder head of the engine for each cylinder. High pressure fuel is dispensed. The high-pressure fuel pipe 26 is provided with a fuel pressure sensor 29 (fuel pressure detection means) for detecting the fuel pressure, and the engine cylinder block is provided with a coolant temperature sensor 32 for detecting the coolant temperature.

これら各種センサの出力は、エンジン制御回路（以下「ＥＣＵ」と表記する）３０に入力される。このＥＣＵ３０は、マイクロコンピュータを主体として構成され、エンジン運転条件に応じて目標燃圧を設定する目標燃圧設定手段として機能すると共に、燃圧センサ２９の検出燃圧（実燃圧）を目標燃圧に一致させるように高圧ポンプ１４の吐出量（燃圧制御弁２２の通電時期）をフィードバック制御する燃圧制御手段としても機能する。   Outputs of these various sensors are input to an engine control circuit (hereinafter referred to as “ECU”) 30. The ECU 30 is mainly composed of a microcomputer, functions as target fuel pressure setting means for setting a target fuel pressure according to engine operating conditions, and matches the detected fuel pressure (actual fuel pressure) of the fuel pressure sensor 29 with the target fuel pressure. It also functions as a fuel pressure control means for feedback control of the discharge amount of the high-pressure pump 14 (energization timing of the fuel pressure control valve 22).

更に、ＥＣＵ３０は、後述する図３の噴射パルス幅算出ルーチンを実行することで、エンジン運転条件に応じて基本噴射パルス幅ＴＰ（基本噴射量）を算出すると共に、燃圧センサ２９の検出燃圧（平滑化処理値）に応じた燃圧補正係数ＫＰと、その他の燃料補正係数ＫＴを算出して、基本噴射パルス幅ＴＰに燃圧補正係数ＫＰとその他の燃料補正係数ＫＴを乗算した値に無効噴射パルス幅ＴＶを加算して最終的な噴射パルス幅ＴＡＵ（燃料噴射量）を求める。
ＴＡＵ＝ＴＰ×ＫＰ×ＫＴ＋ＴＶ Further, the ECU 30 executes an injection pulse width calculation routine shown in FIG. 3 to be described later, thereby calculating the basic injection pulse width TP (basic injection amount) according to the engine operating conditions and detecting the fuel pressure (smooth) of the fuel pressure sensor 29. The fuel pressure correction coefficient KP and the other fuel correction coefficient KT according to the control value) are calculated, and the invalid injection pulse width is obtained by multiplying the basic injection pulse width TP by the fuel pressure correction coefficient KP and the other fuel correction coefficient KT. The final injection pulse width TAU (fuel injection amount) is obtained by adding TV.
TAU = TP × KP × KT + TV

ここで、燃圧補正係数ＫＰを算出する際に用いる燃圧センサ２９の検出燃圧（実燃圧）は、その高周波変動の影響を排除するために、平滑化処理（例えば、なまし処理、一次遅れ処理、フィルタ処理、加重平均演算等）により平滑化した値が用いられる。   Here, the detected fuel pressure (actual fuel pressure) of the fuel pressure sensor 29 used when calculating the fuel pressure correction coefficient KP is smoothed (for example, an annealing process, a first-order lag process, A value smoothed by filtering, weighted average calculation, or the like) is used.

本実施例１では、燃圧センサ２９の検出燃圧の平滑化処理は、図４の検出燃圧平滑化処理ルーチンに従って実行される。これにより、燃圧センサ２９の検出燃圧の変動度合（又は目標燃圧の変化度合）に基づいて燃圧の過渡／定常状態を判定し、その判定結果に応じて検出燃圧の平滑化度合を変更するようにしている。以下、図３及び図４の各ルーチンの処理内容を説明する。   In the first embodiment, the smoothing process of the detected fuel pressure of the fuel pressure sensor 29 is executed according to the detected fuel pressure smoothing process routine of FIG. Thereby, the transient / steady state of the fuel pressure is determined based on the degree of fluctuation of the detected fuel pressure of the fuel pressure sensor 29 (or the degree of change of the target fuel pressure), and the smoothing degree of the detected fuel pressure is changed according to the determination result. ing. Hereinafter, the processing content of each routine of FIG.3 and FIG.4 is demonstrated.

［噴射パルス幅算出ルーチン］
図３の噴射パルス幅算出ルーチンは、ＥＣＵ３０によってエンジン運転中に所定周期で繰り返し実行され、特許請求の範囲でいう噴射パルス幅算出手段としての役割を果たす。本ルーチンが起動されると、まず、ステップ１０１で、エンジン運転条件に基づいて基本噴射パルス幅ＴＰ（基本噴射量）を算出する。この後、ステップ１０２に進み、後述する図４の検出燃圧平滑化処理ルーチンを実行して、単位時間当たりの燃圧センサ２９の検出燃圧の変動量（又は目標燃圧の変化量）に基づいて燃圧の過渡／定常状態を判定し、その判定結果に応じて検出燃圧の平滑化度合を変更して燃圧センサ２９の検出燃圧を平滑化処理する。 [Injection pulse width calculation routine]
The injection pulse width calculation routine of FIG. 3 is repeatedly executed by the ECU 30 at a predetermined cycle during engine operation, and serves as an injection pulse width calculation means in the claims. When this routine is started, first, at step 101, a basic injection pulse width TP (basic injection amount) is calculated based on engine operating conditions. Thereafter, the routine proceeds to step 102, where a detected fuel pressure smoothing processing routine of FIG. 4 described later is executed, and the fuel pressure is detected based on the amount of change in the detected fuel pressure of the fuel pressure sensor 29 per unit time (or the amount of change in the target fuel pressure). The transient / steady state is determined, and the detected fuel pressure of the fuel pressure sensor 29 is smoothed by changing the smoothing degree of the detected fuel pressure according to the determination result.

この後、ステップ１０３に進み、上記ステップ１０２で平滑化処理した検出燃圧を用いて燃圧補正係数ＫＰを算出する。この際、例えば、検出燃圧（平滑化処理値）をパラメータとして燃圧補正係数ＫＰを算出するマップ又は数式を用いて、今回の検出燃圧（平滑化処理値）に応じた燃圧補正係数ＫＰを算出したり、或は、検出燃圧（平滑化処理値）とエンジン負荷をパラメータとして燃圧補正係数ＫＰを算出する二次元マップ又は数式を用いて、今回の検出燃圧（平滑化処理値）とエンジン負荷に応じた燃圧補正係数ＫＰを算出するようにしても良い。これらのマップは、検出燃圧（平滑化処理値）が低くなるほど、燃圧補正係数ＫＰが大きくなって、噴射パルス幅ＴＡＵが増量補正されるように設定されている。   Thereafter, the process proceeds to step 103, and the fuel pressure correction coefficient KP is calculated using the detected fuel pressure smoothed in step 102. At this time, for example, a fuel pressure correction coefficient KP corresponding to the current detected fuel pressure (smoothing process value) is calculated using a map or a mathematical formula for calculating the fuel pressure correction coefficient KP using the detected fuel pressure (smoothing process value) as a parameter. Or, using a detected fuel pressure (smoothing process value) and engine load as parameters, a two-dimensional map or a mathematical formula for calculating the fuel pressure correction coefficient KP, and depending on the current detected fuel pressure (smoothing process value) and engine load. Alternatively, the fuel pressure correction coefficient KP may be calculated. These maps are set so that the fuel pressure correction coefficient KP increases and the injection pulse width TAU is corrected to increase as the detected fuel pressure (smoothing process value) decreases.

この後、ステップ１０４に進み、冷却水温、加減速度合、空燃比学習補正量等を噴射パルス幅ＴＡＵ（燃料噴射量）に反映させるための各種の燃料補正係数ＫＴを算出した後、ステップ１０５に進み、基本噴射パルス幅ＴＰに燃圧補正係数ＫＰとその他の燃料補正係数ＫＴを乗算した値に無効噴射パルス幅ＴＶを加算して最終的な噴射パルス幅ＴＡＵを求める。上記ステップ１０３とステップ１０５の処理によって特許請求の範囲でいう噴射パルス幅補正手段としての役割を果たす。   Thereafter, the process proceeds to step 104, and after calculating various fuel correction coefficients KT for reflecting the cooling water temperature, the acceleration / deceleration rate, the air-fuel ratio learning correction amount and the like in the injection pulse width TAU (fuel injection amount), the process proceeds to step 105. Then, the final injection pulse width TAU is obtained by adding the invalid injection pulse width TV to the value obtained by multiplying the basic injection pulse width TP by the fuel pressure correction coefficient KP and the other fuel correction coefficient KT. The processing of the above step 103 and step 105 serves as an injection pulse width correction means in the claims.

［検出燃圧平滑化処理ルーチン］
図４の検出燃圧平滑化処理ルーチンは、上記図３の噴射パルス幅算出ルーチンのステップ１０２で実行されるサブルーチンであり、特許請求の範囲でいう検出燃圧平滑化処理手段としての役割を果たす。本ルーチンが起動されると、まずステップ２０１で、燃圧センサ２９の検出燃圧を読み込んだ後、ステップ２０２に進み、エンジン始動後であるか否かを判定し、エンジン始動後ではない（つまりエンジン始動時）と判定されれば、ステップ２０７に進み、燃圧センサ２９の検出燃圧を平滑化処理せずに用いる。これにより、エンジン始動時時には、平滑化処理しない検出燃圧（センサ出力値）に基づいて噴射パルス幅を補正すると共に、平滑化処理しない検出燃圧（センサ出力値）を目標燃圧に一致させるように高圧ポンプ１４の吐出量（燃圧制御弁２２の通電時期）をフィードバック制御する。 [Detected fuel pressure smoothing routine]
The detected fuel pressure smoothing process routine of FIG. 4 is a subroutine executed in step 102 of the injection pulse width calculation routine of FIG. 3, and serves as a detected fuel pressure smoothing process means in the claims. When this routine is started, first, at step 201, the fuel pressure detected by the fuel pressure sensor 29 is read, and then the routine proceeds to step 202, where it is determined whether or not the engine has been started. If it is determined, the process proceeds to step 207 where the fuel pressure detected by the fuel pressure sensor 29 is used without being smoothed. As a result, when the engine is started, the injection pulse width is corrected based on the detected fuel pressure (sensor output value) that is not smoothed, and the detected fuel pressure (sensor output value) that is not smoothed is matched with the target fuel pressure. The discharge amount of the pump 14 (the energization timing of the fuel pressure control valve 22) is feedback controlled.

これに対して、上記ステップ２０２で、エンジン始動後であると判定されれば、ステップ２０３に進み、単位時間当たりの検出燃圧の変動量（又は目標燃圧の変化量）が所定の燃圧過渡判定値以内であるか否かで、燃圧の定常／過渡状態を判定する。ここで、燃料噴射弁２８の燃料噴射により燃圧変動が発生することを考慮して、前記燃圧過渡判定値は、単位時間当たりの燃料噴射弁２８の燃料噴射による燃圧変動量を考慮して設定しても良い。或は、高圧ポンプ１４の燃料吐出により燃圧変動が発生することを考慮して、前記燃圧過渡判定値は、単位時間当たりの高圧ポンプ１４の燃料吐出による燃圧変動量を考慮して設定しても良い。勿論、燃料噴射弁２８の燃料噴射による燃圧変動量と高圧ポンプ１４の燃料吐出による燃圧変動量の両方を考慮して燃圧過渡判定値を設定しても良い。このステップ２０３の処理が特許請求の範囲でいう燃圧過渡／定常判定手段としての役割を果たす。   On the other hand, if it is determined in step 202 that the engine has been started, the routine proceeds to step 203 where the fluctuation amount of the detected fuel pressure per unit time (or the change amount of the target fuel pressure) is a predetermined fuel pressure transient determination value. The steady / transient state of the fuel pressure is determined by whether or not it is within the range. Here, considering that fuel pressure fluctuation occurs due to fuel injection of the fuel injection valve 28, the fuel pressure transient determination value is set in consideration of the amount of fuel pressure fluctuation due to fuel injection of the fuel injection valve 28 per unit time. May be. Alternatively, the fuel pressure transient determination value may be set in consideration of the amount of fuel pressure fluctuation due to the fuel discharge of the high pressure pump 14 per unit time in consideration of the occurrence of fuel pressure fluctuation due to the fuel discharge of the high pressure pump 14. good. Of course, the fuel pressure transient determination value may be set in consideration of both the fuel pressure fluctuation amount due to the fuel injection of the fuel injection valve 28 and the fuel pressure fluctuation amount due to the fuel discharge of the high-pressure pump 14. The processing of step 203 serves as a fuel pressure transient / steady state determination means in the claims.

上記ステップ２０３で、単位時間当たりの検出燃圧の変動量（又は目標燃圧の変化量）が所定の燃圧過渡判定値以内であると判定された場合は、燃圧の定常状態と判断して、ステップ２０４に進み、燃圧定常時用の平滑化度合（例えばなまし係数）を算出する。   If it is determined in step 203 that the fluctuation amount of the detected fuel pressure per unit time (or the change amount of the target fuel pressure) is within a predetermined fuel pressure transient determination value, it is determined that the fuel pressure is in a steady state, and step 204 is performed. Then, the smoothing degree (for example, the smoothing coefficient) for steady fuel pressure is calculated.

一方、上記ステップ２０３で、単位時間当たりの検出燃圧の変動量（又は目標燃圧の変化量）が所定の燃圧過渡判定値以内ではないと判定された場合（つまり単位時間当たりの検出燃圧の変動量又は目標燃圧の変化量が燃圧過渡判定値よりも大きい場合）は、燃圧の過渡状態と判断して、ステップ２０５に進み、燃圧過渡時用の平滑化度合（例えばなまし係数）を算出する。ここで、燃圧定常時用の平滑化度合は、燃圧の高周波変動の影響排除を優先して、燃圧過渡時用の平滑化度合よりも大きい値に設定され、燃圧過渡時用の平滑化度合は、燃圧追従性を優先して、燃圧定常時用の平滑化度合よりも小さい値に設定されている。   On the other hand, if it is determined in step 203 that the fluctuation amount of the detected fuel pressure per unit time (or the change amount of the target fuel pressure) is not within the predetermined fuel pressure transient determination value (that is, the fluctuation amount of the detected fuel pressure per unit time). Alternatively, if the change amount of the target fuel pressure is larger than the fuel pressure transient determination value, it is determined that the fuel pressure is in a transient state, the process proceeds to step 205, and a smoothing degree (for example, an annealing coefficient) for the fuel pressure transient is calculated. Here, the smoothing degree for steady fuel pressure is set to a value larger than the smoothing degree for fuel pressure transient, giving priority to eliminating the effects of high-frequency fluctuations in fuel pressure, and the smoothing degree for fuel pressure transient is The fuel pressure followability is prioritized and is set to a value smaller than the smoothing degree for steady fuel pressure.

この後、ステップ２０６に進み、上記ステップ２０４又はステップ２０５で算出した平滑化度合を用いて燃圧センサ２９の検出燃圧を平滑化処理する。例えば、平滑化処理として、なまし処理を用いる場合は、平滑化度合であるなまし係数αを用いて、次式により燃圧センサ２９の検出燃圧をなまし処理する。
Ｐav(i) ＝Ｐav(i-1) ×α＋Ｐ×（１−α） Thereafter, the process proceeds to step 206, and the fuel pressure detected by the fuel pressure sensor 29 is smoothed using the smoothing degree calculated in step 204 or 205. For example, when the smoothing process is used as the smoothing process, the detected fuel pressure of the fuel pressure sensor 29 is smoothed by the following formula using the smoothing coefficient α which is the smoothing degree.
Pav (i) = Pav (i-1) × α + P × (1−α)

上式において、Ｐav(i) は今回の検出燃圧なまし処理値、Ｐav(i-1) は前回の検出燃圧なまし処理値、Ｐは燃圧センサ２９の検出燃圧（センサ出力値）である。なまし係数αは０＜α＜１である。   In the above equation, Pav (i) is the current detected fuel pressure smoothing value, Pav (i-1) is the previous detected fuel pressure smoothing value, and P is the detected fuel pressure (sensor output value) of the fuel pressure sensor 29. The annealing coefficient α is 0 <α <1.

以上説明した本実施例１によれば、燃圧センサ２９の検出燃圧の変動度合（又は目標燃圧の変化度合）に基づいて燃圧の過渡／定常状態を判定し、その判定結果に応じて当該検出燃圧の平滑化度合を変更するようにしたので、エンジンの過渡運転時でも目標燃圧が変化しない場合は、実燃圧（燃圧センサ２９の検出燃圧）の変動も少ないと判断して、検出燃圧の平滑化度合を燃圧追従性を高める方向に変更することを回避して燃圧の高周波変動の影響を排除することが可能となり、また、エンジンの定常運転時でも目標燃圧が変化すれば、検出燃圧の平滑化度合を燃圧追従性を高める方向に変更して実燃圧を応答良く目標燃圧に追従させることが可能となる。これにより、実燃圧の変動度合に応じて燃圧センサ２９の検出燃圧の平滑化処理を適正化して空燃比制御精度を向上させることができる。   According to the first embodiment described above, the transient / steady state of the fuel pressure is determined based on the degree of fluctuation of the detected fuel pressure of the fuel pressure sensor 29 (or the degree of change of the target fuel pressure), and the detected fuel pressure is determined according to the determination result. Therefore, if the target fuel pressure does not change even during the transient operation of the engine, it is determined that the actual fuel pressure (the detected fuel pressure of the fuel pressure sensor 29) is small and the detected fuel pressure is smoothed. It is possible to eliminate the influence of high-frequency fluctuations in fuel pressure by avoiding changing the degree to improve the fuel pressure followability, and to smooth the detected fuel pressure if the target fuel pressure changes even during steady engine operation It is possible to change the degree in the direction of improving the fuel pressure followability and make the actual fuel pressure follow the target fuel pressure with good response. Thereby, the smoothing process of the detected fuel pressure of the fuel pressure sensor 29 can be optimized according to the fluctuation degree of the actual fuel pressure, and the air-fuel ratio control accuracy can be improved.

ところで、エンジン始動時には実燃圧が非常に大きく変動するため、エンジン始動時に燃圧センサ２９の検出燃圧を平滑化処理すると、検出燃圧と実燃圧とのずれが平滑化処理により拡大されてしまい、エンジン始動時の噴射パルス幅補正精度が悪化する可能性がある。   By the way, since the actual fuel pressure fluctuates greatly when the engine is started, if the detected fuel pressure of the fuel pressure sensor 29 is smoothed when the engine is started, the deviation between the detected fuel pressure and the actual fuel pressure is expanded by the smoothing process. There is a possibility that the injection pulse width correction accuracy at that time may deteriorate.

この点を考慮して、本実施例１では、エンジン始動時には、検出燃圧の平滑化処理を行わず、平滑化処理されない検出燃圧（センサ出力値）に基づいて噴射パルス幅を補正するようにしているため、エンジン始動時に検出燃圧の平滑化処理により検出燃圧と実燃圧とのずれが拡大されて噴射パルス幅補正精度が悪化する事態を回避することができる。   Considering this point, in the first embodiment, when the engine is started, the detected fuel pressure is not smoothed, and the injection pulse width is corrected based on the detected fuel pressure (sensor output value) that is not smoothed. Therefore, it is possible to avoid a situation in which the deviation between the detected fuel pressure and the actual fuel pressure is increased by the smoothing process of the detected fuel pressure when the engine is started and the injection pulse width correction accuracy deteriorates.

上記実施例１では、エンジン始動時には、検出燃圧の平滑化処理を行わず、平滑化処理されない検出燃圧（センサ出力値）に基づいて噴射パルス幅を補正するようにしたが、本発明の実施例２では、図３の噴射パルス幅算出ルーチンのステップ１０２で図５の検出燃圧平滑化処理ルーチンを実行することで、エンジン始動時には、始動後とは異なる始動時用の平滑化度合を算出して、始動時用の平滑化度合を用いて燃圧センサ２９の検出燃圧を平滑化処理するようにしている（ステップ２０８）。   In the first embodiment, when the engine is started, the detected fuel pressure is not smoothed, and the injection pulse width is corrected on the basis of the detected fuel pressure (sensor output value) that is not smoothed. 2, the detected fuel pressure smoothing processing routine of FIG. 5 is executed in step 102 of the injection pulse width calculation routine of FIG. 3 to calculate a smoothing degree for starting different from that after starting when the engine is started. The fuel pressure detected by the fuel pressure sensor 29 is smoothed using the smoothing degree for starting (step 208).

一般に、始動時用の平滑化度合は、始動後の平滑化度合（燃圧定常時用の平滑化度合や燃圧過渡時用の平滑化度合）よりも小さい値に設定すれば良いと思われるが、エンジン始動時の燃圧制御能力等によっては始動時用の平滑化度合を始動後の平滑化度合よりも大きい値に設定することも考えられる。その他のステップ２０１〜２０６の処理は、前記実施例１で説明した図４の検出燃圧平滑化処理ルーチンの各ステップ２０１〜２０６の処理と同じである。   In general, the smoothing degree for start-up may be set to a value smaller than the smoothing degree after start-up (smoothing degree for steady fuel pressure or smoothing degree for fuel pressure transient), Depending on the fuel pressure control capability at the start of the engine, etc., it may be possible to set the smoothing degree for starting to a value larger than the smoothing degree after starting. The other processes of steps 201 to 206 are the same as the processes of steps 201 to 206 of the detected fuel pressure smoothing process routine of FIG. 4 described in the first embodiment.

以上説明した本実施例２でも、エンジン始動時に、始動時に適した平滑化度合で検出燃圧の平滑化処理を行うことが可能となり、始動時の噴射パルス幅補正精度が悪化することを回避することができる。   Even in the second embodiment described above, it is possible to perform the smoothing process of the detected fuel pressure with a smoothing degree suitable at the time of starting the engine, and avoid deterioration of the injection pulse width correction accuracy at the time of starting. Can do.

本発明の実施例１，２における燃料噴射システム全体の概略構成を示す図である。It is a figure which shows schematic structure of the whole fuel-injection system in Example 1, 2 of this invention. 高圧ポンプの構成図である。It is a block diagram of a high pressure pump. 実施例１，２で実行する噴射パルス幅算出ルーチンの処理の流れを示すフローチャートである。6 is a flowchart showing a flow of processing of an injection pulse width calculation routine executed in Examples 1 and 2. 実施例１で実行する検出燃圧平滑化処理ルーチンの処理の流れを示すフローチャートである。3 is a flowchart showing a flow of processing of a detected fuel pressure smoothing processing routine executed in the first embodiment. 実施例２で実行する検出燃圧平滑化処理ルーチンの処理の流れを示すフローチャートである。6 is a flowchart showing a flow of processing of a detected fuel pressure smoothing processing routine executed in Embodiment 2.

符号の説明Explanation of symbols

１１…燃料タンク、１２…低圧ポンプ、１４…高圧ポンプ、１９…ピストン、２０…カム軸、２１…カム、２２…燃圧制御弁、２５…逆止弁、２６…高圧燃料配管、２７…デリバリパイプ、２８…燃料噴射弁、２９…燃圧センサ（燃圧検出手段）、３０…ＥＣＵ（噴射パルス幅算出手段，検出燃圧平滑化処理手段，噴射パルス幅補正手段，燃圧過渡／定常判定手段，目標燃圧設定手段）   DESCRIPTION OF SYMBOLS 11 ... Fuel tank, 12 ... Low pressure pump, 14 ... High pressure pump, 19 ... Piston, 20 ... Cam shaft, 21 ... Cam, 22 ... Fuel pressure control valve, 25 ... Check valve, 26 ... High pressure fuel piping, 27 ... Delivery pipe , 28 ... fuel injection valve, 29 ... fuel pressure sensor (fuel pressure detection means), 30 ... ECU (injection pulse width calculation means, detected fuel pressure smoothing processing means, injection pulse width correction means, fuel pressure transient / steady state determination means, target fuel pressure setting means)

Claims (8)

燃料を高圧にして燃料噴射弁に供給する高圧ポンプと、内燃機関の運転条件に応じて前記燃料噴射弁を駆動する噴射パルス幅を算出する噴射パルス幅算出手段とを備え、前記噴射パルス幅で前記燃料噴射弁を駆動して燃料を気筒内に直接噴射する筒内噴射式内燃機関の燃料噴射制御装置において、
前記高圧ポンプにより前記燃料噴射弁に供給される燃料の圧力（以下「燃圧」という）を検出する燃圧検出手段と、
前記燃圧検出手段の検出燃圧を平滑化処理する検出燃圧平滑化処理手段と、
前記検出燃圧平滑化処理手段で平滑化処理された検出燃圧に基づいて前記噴射パルス幅を補正する噴射パルス幅補正手段とを備え、
前記検出燃圧平滑化処理手段は、前記燃圧検出手段の検出燃圧の変動度合に基づいて燃圧の過渡／定常状態を判定する燃圧過渡／定常判定手段と、前記燃圧の過渡／定常状態の判定結果に応じて前記検出燃圧の平滑化度合を変更する手段とを備えていることを特徴とする筒内噴射式内燃機関の燃料噴射制御装置。 A high-pressure pump for supplying fuel to the fuel injection valve at a high pressure; and an injection pulse width calculation means for calculating an injection pulse width for driving the fuel injection valve in accordance with an operating condition of the internal combustion engine. In a fuel injection control device for a direct injection internal combustion engine that drives the fuel injection valve and directly injects fuel into the cylinder,
Fuel pressure detecting means for detecting the pressure of fuel supplied to the fuel injection valve by the high pressure pump (hereinafter referred to as “fuel pressure”);
Detected fuel pressure smoothing processing means for smoothing the detected fuel pressure of the fuel pressure detecting means;
Injection pulse width correcting means for correcting the injection pulse width based on the detected fuel pressure smoothed by the detected fuel pressure smoothing processing means,
The detected fuel pressure smoothing processing means includes a fuel pressure transient / steady state determination means for determining a transient / steady state of the fuel pressure based on a degree of fluctuation of the detected fuel pressure of the fuel pressure detection means, and a determination result of the transient / steady state of the fuel pressure. And a means for changing the smoothing degree of the detected fuel pressure accordingly . 前記検出燃圧平滑化処理手段は、燃圧過渡状態と判定した時の前記検出燃圧の平滑化度合を燃圧定常状態と判定した時の前記検出燃圧の平滑化度合よりも小さい値に設定することを特徴とする請求項１に記載の筒内噴射式内燃機関の燃料噴射制御装置。 The detected fuel pressure smoothing processing means sets the smoothed degree of the detected fuel pressure when determined as a fuel pressure transient state to a value smaller than the smoothed degree of the detected fuel pressure when determined as a steady fuel pressure state. The fuel injection control device for a direct injection internal combustion engine according to claim 1. 前記燃圧過渡／定常判定手段は、単位時間当たりの検出燃圧の変動量が所定の燃圧過渡判定値以上であることを検出したときに燃圧過渡状態と判定することを特徴とする請求項２に記載の筒内噴射式内燃機関の燃料噴射制御装置。   The fuel pressure transient / steady state determination means determines that the fuel pressure is in a transient state when detecting that the fluctuation amount of the detected fuel pressure per unit time is not less than a predetermined fuel pressure transient determination value. A fuel injection control device for an in-cylinder internal combustion engine. 前記燃圧過渡判定値は、単位時間当たりの前記燃料噴射弁の燃料噴射による燃圧変動量を考慮して設定されていることを特徴とする請求項３に記載の筒内噴射式内燃機関の燃料噴射制御装置。   The fuel injection of the direct injection internal combustion engine according to claim 3, wherein the fuel pressure transient determination value is set in consideration of a fuel pressure fluctuation amount due to fuel injection of the fuel injection valve per unit time. Control device. 前記燃圧過渡判定値は、単位時間当たりの前記高圧ポンプの燃料吐出による燃圧変動量を考慮して設定されていることを特徴とする請求項３又は４に記載の筒内噴射式内燃機関の燃料噴射制御装置。   The fuel of the direct injection internal combustion engine according to claim 3 or 4, wherein the fuel pressure transient determination value is set in consideration of a fuel pressure fluctuation amount due to fuel discharge of the high pressure pump per unit time. Injection control device. 燃料を高圧にして燃料噴射弁に供給する高圧ポンプと、内燃機関の運転条件に応じて前記燃料噴射弁を駆動する噴射パルス幅を算出する噴射パルス幅算出手段とを備え、前記噴射パルス幅で前記燃料噴射弁を駆動して燃料を気筒内に直接噴射する筒内噴射式内燃機関の燃料噴射制御装置において、
前記高圧ポンプにより前記燃料噴射弁に供給される燃料の圧力（以下「燃圧」という）を検出する燃圧検出手段と、
内燃機関の運転条件に応じて目標燃圧を設定する目標燃圧設定手段と、
前記燃圧検出手段の検出燃圧を平滑化処理する検出燃圧平滑化処理手段と、
前記検出燃圧平滑化処理手段で平滑化処理された検出燃圧に基づいて前記噴射パルス幅を補正する噴射パルス幅補正手段とを備え、
前記検出燃圧平滑化処理手段は、前記目標燃圧の変化度合に基づいて燃圧の過渡／定常状態を判定する燃圧過渡／定常判定手段と、前記燃圧の過渡／定常状態の判定結果に応じて前記検出燃圧の平滑化度合を変更する手段とを備えていることを特徴とする筒内噴射式内燃機関の燃料噴射制御装置。 A high-pressure pump for supplying fuel to the fuel injection valve at a high pressure; and an injection pulse width calculation means for calculating an injection pulse width for driving the fuel injection valve in accordance with an operating condition of the internal combustion engine. In a fuel injection control device for a direct injection internal combustion engine that drives the fuel injection valve and directly injects fuel into the cylinder,
Fuel pressure detecting means for detecting the pressure of fuel supplied to the fuel injection valve by the high pressure pump (hereinafter referred to as “fuel pressure”);
Target fuel pressure setting means for setting a target fuel pressure according to the operating conditions of the internal combustion engine;
Detected fuel pressure smoothing processing means for smoothing the detected fuel pressure of the fuel pressure detecting means;
Injection pulse width correcting means for correcting the injection pulse width based on the detected fuel pressure smoothed by the detected fuel pressure smoothing processing means,
The detected fuel pressure smoothing processing means includes a fuel pressure transient / steady state determination means for determining a transient / steady state of the fuel pressure based on a degree of change in the target fuel pressure, and the detection according to a determination result of the transient / steady state of the fuel pressure. A fuel injection control device for a direct injection internal combustion engine, comprising: means for changing a smoothing degree of the fuel pressure . 前記検出燃圧平滑化処理手段は、燃圧過渡状態と判定した時の前記検出燃圧の平滑化度合を燃圧定常状態と判定した時の前記検出燃圧の平滑化度合よりも小さい値に設定することを特徴とする請求項６に記載の筒内噴射式内燃機関の燃料噴射制御装置。 The detected fuel pressure smoothing processing means sets the smoothed degree of the detected fuel pressure when determined as a fuel pressure transient state to a value smaller than the smoothed degree of the detected fuel pressure when determined as a steady fuel pressure state. A fuel injection control device for a direct injection internal combustion engine according to claim 6. 燃料を高圧にして燃料噴射弁に供給する高圧ポンプと、内燃機関の運転条件に応じて前記燃料噴射弁を駆動する噴射パルス幅を算出する噴射パルス幅算出手段とを備え、前記噴射パルス幅で前記燃料噴射弁を駆動して燃料を気筒内に直接噴射する筒内噴射式内燃機関の燃料噴射制御装置において、
前記高圧ポンプにより前記燃料噴射弁に供給される燃料の圧力（以下「燃圧」という）を検出する燃圧検出手段と、
前記燃圧検出手段の検出燃圧を平滑化処理する検出燃圧平滑化処理手段と、
前記検出燃圧平滑化処理手段で平滑化処理された検出燃圧に基づいて前記噴射パルス幅を補正する噴射パルス幅補正手段を備え、
前記検出燃圧平滑化処理手段は、内燃機関の始動時には前記検出燃圧の平滑化処理を行わず、始動後に前記検出燃圧の平滑化処理を開始し、
前記噴射パルス幅補正手段は、内燃機関の始動時には平滑化処理されない検出燃圧に基づいて前記噴射パルス幅を補正し、始動後には平滑化処理された検出燃圧に基づいて前記噴射パルス幅を補正することを特徴とする筒内噴射式内燃機関の燃料噴射制御装置。 A high-pressure pump for supplying fuel to the fuel injection valve at a high pressure; and an injection pulse width calculation means for calculating an injection pulse width for driving the fuel injection valve in accordance with an operating condition of the internal combustion engine. In a fuel injection control device for a direct injection internal combustion engine that drives the fuel injection valve and directly injects fuel into the cylinder,
Fuel pressure detecting means for detecting the pressure of fuel supplied to the fuel injection valve by the high pressure pump (hereinafter referred to as “fuel pressure”);
Detected fuel pressure smoothing processing means for smoothing the detected fuel pressure of the fuel pressure detecting means;
An injection pulse width correcting means for correcting the injection pulse width based on the detected fuel pressure smoothed by the detected fuel pressure smoothing processing means;
The detected fuel pressure smoothing processing means does not perform the detected fuel pressure smoothing process when starting the internal combustion engine, and starts the detected fuel pressure smoothing process after starting,
The injection pulse width correction means corrects the injection pulse width based on the detected fuel pressure that is not smoothed when the internal combustion engine is started, and corrects the injection pulse width based on the detected fuel pressure that is smoothed after the start. A fuel injection control device for a cylinder injection type internal combustion engine.
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